First of all, this is not "Core's decision". Bech32 was not created by "Core" and has not yet been adopted and implemented by the other developers of Core. It is the proposal of a few people who work on Core but they are not and do not represent Core.

First of all, this is not "Core's decision". Bech32 was not created by "Core" and has not yet been adopted and implemented by the other developers of Core. It is the proposal of a few people who work on Core but they are not and do not represent Core.

I have read that explanation before. So that's exactly my question. Now that "B1" is even shorter and distinguishable, why they chose "BC1“? Was there any technical reason? I read that BIP again and could not find any other explanation.

BTW, now that that BIP was proposed by Blockstream, it's extremely likely that it will gain "consensus", sooner or later. However, the blockstream-style logic always sounds weird to me.